Arthur William Gerald Kingsbury was born in East Meon, Hampshire, England, the eldest son of Gerald F. Kingsbury, a farmer. He received a classical education at Bradfield College in Berkshire (a prep school), and would have preferred to study for a university degree but instead was compelled by his family to apprentice with a London law firm. He passed his bar exam in 1929 and became a solicitor (attorney) in the West Country, first at Sherborne and then at Crewkerne.

Kingsbury's family had an interest in natural history which surely inspired his attraction to mineralogy. He mother's relatives were ornithologists, and his paternal great-grandfather, Thomas Kingsbury (1777-1854), had built a mineral collection through his regular travels to Cornwall. His grandfather, William Joseph Kingsbury (1825-1904), a prominent civil engineer, added to the collection. Kingsbury began field-collecting minerals himself in 1927, on trips through Cornwall, Devon and the Mendip Hills. Through the influence of Dr. Leonard J. Spencer (1870-1959) at the British Museum and the prominent collector Sir Arthur Russell (1878-1964), Kingsbury intensified his field work and published some of his findings in 1939-1941. In 1941 he married Philippa Margaret James, and together they had two children, Martin and Lucilla.

Kingsbury had really wanted to become a mineralogy curator but instead took the position of Managing Director of a small engineering company during the war, finally leaving industrial life in 1946. The following year he found a position much more to his liking, as research assistant in the mineralogy department of the Oxford University Museum. He had an acute ability to sight-identify minerals; he collected in the field extensively and added 50 species to the list of minerals known to occur in Great Britain. He published over two dozen articles in the 1950s and 1960s on new occurrences of various minerals in Ebngland.

Kingsbury assembled a major collection of minerals, incorporating those of his ancestors and assimilating other collections as well (at least the British specimens in them), including those of: Misses M.A. and L. Haycock, his wife's maternal grandfather (Lord Shuttleworth of Gawthorpe Hall, Lancashire), W.R. Storr of Bristol, W. Semmons (and employee of the Tincroft and Carn Brae mines in Cornwall), Thomas Warburton of Highbury, London, and specimens from the famous collection of the Baroness Burdett-Coutts (1814-1906). Kingsbury's collection was eventually donated to the British Museum by his children, along with his field notes and annotated maps.

Kingsbury received numerous honors during his life. He was elected a Fellow of the Geological Society of London and the Mineralogical Society of America (1960), was granted a Master of Arts Degree by Oxford University in 1968, and was awarded the Bolitho Medal by the Royal Geological Society of Cornwall in 1957, in recognition of his contributions to Cornish mineralogy. The mineral arthurite was named jointly for him and his friend Sir Arthur Russell in 1964, by R.J. Davis and Max Hey; both men had submitted specimens of the new species for study. Kingsbury was also a competent guitarist, a photographer of birds, and a prominent wine aficionado.

Despite his accomplishments, Kingsbury's reputation was tarnished somewhat by the fact that he had falsified many of the localities for his purported field discoveries; there was no financial gain involved, so it has been surmised that he was attempting to gain notoriety as a successful field collector in competition with his friend Sir Arthur Russell. He died on August 3, 1968, at the age of 62.